Turbine systems are widely utilized in fields such as power generation. For example, a conventional gas turbine system includes a compressor section, a combustor section, and at least one turbine section. The compressor section is configured to compress air as the air flows through the compressor section. The air is then flowed from the compressor section to the combustor section, where it is mixed with fuel and combusted, generating a hot gas flow. The hot gas flow is provided to the turbine section, which utilizes the hot gas flow by extracting energy from it to power the compressor, an electrical generator, and other various loads.
The combustor sections of turbine systems generally include tubes or ducts for flowing the combusted hot gas therethrough to the turbine section or sections. Recently, combustor sections have been introduced which include tubes or ducts that shift the flow of the hot gas. For example, ducts for combustor sections have been introduced that, while flowing the hot gas longitudinally therethrough, additionally shift the flow radially or tangentially such that the flow has various angular components. These designs have various advantages, including eliminating first stage nozzles from the turbine sections. The first stage nozzles were previously provided to shift the hot gas flow, and may not be required due to the design of these ducts. The elimination of first stage nozzles may eliminate associated pressure drops and increase the efficiency and power output of the turbine system.
However, the connection of these ducts to each other is of increased concern. For example, because the ducts do not simply extend along a longitudinal axis, but are rather shifted off-axis from the inlet of the duct to the outlet of the duct, thermal expansion of the ducts can cause undesirable shifts in the ducts along or about various axes. Such shifts can cause unexpected gaps between the adjacent ducts, thus undesirably allowing leakage and mixing of cooling air and hot gas.
This problem is of particular concern due to the interaction between the adjacent ducts. For example, in many embodiments an airfoil trailing edge is formed by adjacent ducts. This airfoil may shift the hot gas flow in the ducts, and thus eliminate the need for first stage nozzles. However, because the airfoil is formed by the adjacent ducts, any gaps between the ducts can allow leakage and mixing which can interfere with the performance of the airfoil.
Accordingly, an improved seal between adjacent combustor ducts in a turbine system would be desired in the art. For example, a seal that allows for thermal growth of the adjacent ducts while preventing gaps between the adjacent ducts would be advantageous.